problems with long long variable type

Question

I´ve been looking over internet and through the man cs50.h to find out why a simple program like this generates values error from 8 onwards, but i couldn't find why reads a value and stores another. It will be nice to find help on this particular issue. Thankyou.

#include <stdio.h>
#include <cs50.h>

int main ()
{
    unsigned long long card_number;
    card_number =  0 ;
    card_number = GetLongLong();
    printf ("%llo \n",card_number);
}

Answer 1

No need to initialize card_number to 0 before you initialize it to GetLongLong().

Your variable doesn't really store a different value. Actually, you don't print your value the correct way. To print a long long, you should use %lld not %llo

#include <stdio.h>

int main(void)
{
    unsigned long long x = 4111111111111111;
    printf("%llo\n", x);
    printf("%lld\n", x);
}

Output:

164660424532170707
4111111111111111

The %llo format is used for representing a long long value in octal. See more!

Answer 2

GetLongLong() returns a long long, not an unsigned long long as you've declared. Perhaps that's the problem you are experiencing?